Briefly, taxotere is a novel semisynthetic analogue of taxol which is prepared from a precursor extracted from the needles, rather than the bark of Taxus brevifolia. Thus, the supply of taxotere is significantly more stable and predictable than that of the parent compound Taxol. In vitro experiments have shown that taxotere, like taxol, induces the formation of microtubule bundles that are stable in the presence of depolymerizing agents such as Ca and low temperature. This results in cytotoxicity by blocking cells at either the G2 or M phase of the cell cycle. Taxotere has been shown to be slightly more active than taxol in promoting tubulin polymerization. In addition, preclinical studies have demonstrated that taxotere has superior in vivo activity versus Taxol in some murine tumor models.